Knowledge Feature – Flakes

Photo: One of two large bags we managed to fill with flakes on an excavation in Edmonton, Ab.

I’m not a lithics expert.  I want to get that out there, into the open, so that people know there are others out there who know a whole lot more than I do about lithics.  That being said, lithics are something I’ve encountered on nearly every archaeological excavation I’ve been part of, and are easily one of the most common categories of artifacts found on archaeological sites.  If not THE most common.  So it pays to be aware of them and be able to recognize them when you’ve got them.

‘Lithic‘ is a fancy way of saying ‘stone’.  Lithics are stone artifacts that include both tools (like projectile points, scrapers, and adzes) and the debitage (fancy word for saying the garbage from working with stone, which also has a fancy title of ‘lithic reduction‘), produced while making them.  Lithic debitage generally consists of flakes, which is the portion of a rock removed to make a tool (either the flake becomes the tool or is removed from the tool), and cores, which is the part of the rock which has had flakes removed from it.  Of lithic tools, cores, and flakes, flakes tend to be the most common lithic item to appear on sites.  At least in my experience.  I’ve definitely seen far more flakes than cores or lithic tools.  So that’s why I want to talk about them.  If you’re going to be encountering flakes, than it’s going to help to know how to identify them.

Click to access flint_id_guide.pdf

Check out the link I’ve posted above for some fantastic illustrations and photos.  It’s an extremely useful guide.  It was produced by British archaeologists, but flakes from all corners of the world share the same basic characteristics used for identifying them.  I’ve seen flakes in BC, Alberta, and Ontario.  They all look the same.  I’ve even seen gun flints from my work in Ontario that look IDENTICAL to the ones pictured in that guide.  What I’m trying to say is that this British guide will be useful to you no matter where you are.  Tools, of course, will look very different because those are regionally dependent.  But for flakes this guide is great.  My good friend Wikipedia also has some useful information for you (https://en.wikipedia.org/wiki/Lithic_flake)

First of all, there are 3 types of flakes differentiated by the sequence of lithic reduction in which they are produced.  The cortex of a rock is the weathered outer portion of a rock protecting the inner, unweathered part (think of it as an orange peel).  Primary flakes are flakes which still have the cortex entirely covering one side of the flake (referred to as the dorsal side). Secondary flakes have some traces of cortex still on them, but not a lot.  And tertiary flakes have no cortex at all, meaning they’ve been produced entirely of the inside of the rock.  These tertiary flakes are generally associated with retouching stages of tool production, which refers to the final stages of turning a plain old rock into a fancy tool (though primary and secondary flakes can also be used as tools).

There are also 4 styles of breaking points for flakes, called the termination type.  This refers to the manner in which the distal end of the flake physically detached from the core. Feathered terminations are very sharp, fine, tapered distal ends.  Hinged terminations are rounded distal ends caused by the force of impact rolling away away from the core.  Step terminations are caused by the flake breaking too early, leaving it with a squared distal end.  Plunged terminations result from the force of impact rolling
backwards and breaking both ends of the flakes off the core.  Also referred to as outrepasse or overshot, these termination types best illustrated by the flake scars (marks left on the core where a flake was removed) on Clovis points, which extend across the entire point from side to side.

 

 

So how do we identify a flake as being a flake?  We look for 4 main features:

1. Striking platform – a flat surface where the blow (the hit that separates the flake from the core) strikes
2. Bulb of percussion – a little spot of swelling immediately below the point of impact
3. Bulbar scar – where a small chip is missing right beneath the bulb of percussion (though this isn’t seen on every single flake)
4. Waves of percussion – (the British guide refers to them as ripples, which is exactly what they look like) waves radiating out and away from the bulb of percussion down part of the flake

   

So there you have it. Keep your eyes open for these 4 features to help you identify whether or not the rock in your hand is just a rock or if it’s a man-made flake.  Happy identifying!

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